Why Do Beans Give You Flatulence?

by Jessica Bruso

A large bowl of pinto beans.

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Beans provide significant amounts of fiber, protein, vitamins and minerals, making them an inexpensive way to increase the nutritional quality of your diet. Some people are put off, however, by their gas-producing potential. While beans can cause an increase in flatulence in some people, you can minimize this effect with certain preparation techniques.

Carbohydrate Considerations

Certain types of sugars and fiber found in beans can lead to an increased production of gas. The sugars raffinose and stachyose, both of which aren't well-digested, and the soluble fiber in beans are the main culprits when it comes to flatulence. Suddenly increasing your fiber intake, especially if you don't also increase the amount of water you consume, can overwhelm the bacteria in your colon that help break down the fiber in your diet. This breakdown occurs through the fermentation of soluble fiber, a byproduct of which is gas.

Type of Bean

Some beans are less likely to increase flatulence than others. A study published in the "Nutrition Journal" in 2011 found that while 50 percent of participants believed they had an increase in gas production after consuming 1/2 cup per day of baked beans or pinto beans, only 19 percent reported an increase after consuming the same amount of black-eyed peas -- a type of bean, despite its name -- for a week. Trial and error can help you determine which beans are most likely to cause you to have flatulence.

Preparation Method

If you don't rinse either canned or soaked raw beans before you cook them, they are more likely to cause gas. Soak your raw beans using a hot soaking method, which involves boiling water and then soaking beans for four hours, instead of soaking your beans overnight in cold water, to limit gas production even more, recommends North Dakota State University Extension. The hot soaking method causes more of the gas-producing sugars to be released into the soaking water, which you discard before preparing the beans.

Reducing the Effect

If gas is a problem when you eat beans, try taking an over-the-counter supplement containing the enzyme alpha-galactosidase before you eat them. Increase the amount of beans and other fiber-rich foods you eat gradually, drink plenty of water and chew your beans well to make them easier to digest, recommends North Dakota State University Extension.